White EPDM Technology Evolution

White EPDM, a 33-year history of evolution and innovation.

Since the introduction of white EPDM roofs in 1987, numerous enhancements have been made to the membrane and system components, making today’s white EPDM systems far more robust and a greater value than ever before. There are four main areas in which major enhancements have been made to white EPDM system technology: improving performance and increasing value.

Improvements to the Membrane
When white EPDM membrane was introduced over 33 years ago, single-ply commercial roofing systems were routinely marketed with a 10-year warranty. As time marched on and experience was gained, the warranty terms started increasing for 60-mil white EPDM membrane. First to 15 years in 2001, 20 years in 2007, and then 25 years in 2015. While the original white EPDM had respectable UV weathering resistance for the time, it was apparent that a trend towards longer term performance was evolving. With that in mind, the EPDM chemists in R&D went to work on formulating a higher-performing white EPDM that was implemented into production in December of 1994. The industry standard test for UV resistance is the Xenon Arc accelerated weathering test, and our white EPDM now boasts an impressive 25,200 kJ/m2; which is one of the highest levels among white single-ply membranes.

For the first 21 years, white EPDM was only available in 10’ widths. In 2008, we introduced wider sheet options of 16.5’ and 20’ to support the growing use of EPDM on larger, wide-open type projects. Seaming labor was cut by 36% and 50% respectively, compared to 10’-wide sheets.

Improvements to Seams
The second area of improvement was in EPDM seaming technology. In the late-1980s, Carlisle was using a specially designed splice wash to clean the seam area, and a butyl-based white splice cement. Butyl-based splice adhesives had been used in pond liner applications and are very tolerant of ponded water. However, the seaming process involved quite a few steps, leaving seams prone to variations caused by workmanship techniques and installation conditions. There were several nuances to using white splice cement that were at times missed, as people assumed it would install the same as the black version. Temperature, humidity, and flash-off points all played a larger role with the white splice cement as people learned.

In 2001, Carlisle introduced a customized splice primer and double-sided white seam tape. These products simplified the seaming process and reduced workmanship inconsistencies. The more variability taken out of a process, the more consistent the results. During this time, Carlisle also developed pre-cleaned 10’-wide sheets, eliminating the membrane cleaning step, and allowed for roller application of splice primer.

Around 2005, Carlisle took seaming to the next level by introducing EPDM sheets with Factory-Applied Tape, in which splice primer and splice tape are pre-applied to one side of the sheet in a factory-controlled environment. This breakthrough in technology further decreased workmanship issues and improved the quality of finished splices, because contractors simply had to roller-apply primer to one side of the sheet and then mate the two sheets together with a seam roller.

Factory-Applied Tape not only improved seaming productivity by 65%, it also improved seam quality so dramatically that Carlisle saw an 80% drop in seam-related warranty claims. Today, applicators are reporting fewer call-backs for workmanship issues on EPDM seams than other non-EPDM single-ply seams.

Improvements to Puncture Resistance
Non-reinforced 60-mil EPDM membranes are quite popular and offer a full 60 mils of weathering protection. In comparison, internally reinforced membranes of any type contain less weathering material over the reinforcing scrim. For example, on a 60-mil reinforced sheet, the thickness over scrim ranges from 20 to 25 mils.

In 1996, we introduced a fleece-backed EPDM sheet featuring the highest puncture resistance of all EPDM membranes. For a 60-mil membrane, adding external fleece reinforcement increases puncture resistance by approximately 300%. Because the sheet is externally reinforced, fleece-backed membranes contain a full 60 mils of weathering material above the reinforcement.

In 2012, Carlisle introduced 90-mil white EPDM, which has considerably more puncture resistance and provides the most weathering material of any single-ply membrane on the market.

Improvements to Flashing Details
White flashing made of uncured EPDM was introduced along with white EPDM membrane in 1987. Uncured EPDM flashing offered the same weathering properties and required the use of white splice cement, which as mentioned before, had some installation nuances

In 1992, wall and curb flashing details were updated to require cured (as opposed to uncured) EPDM membrane for added toughness, durability, UV resistance, and weatherability. This was a natural progression with the introduction of the RUSS detail that allowed the high-performance EPDM field membrane to run continuously into the angle change and up the wall.

In 2005, Carlisle introduced a line of prefabricated pressure-sensitive inside/outside corners, pipe boots, and pourable sealer pockets for white EPDM systems. These products quickly gained popularity because they simplified the application process and improved the quality of the finished roofing system. Today’s pressure-sensitive flashings feature a full 60-mil EPDM weathering layer laminated to 30-mil cured adhesive for a 90-mil total thickness. This added thickness contributes to the durability and robustness of white EPDM flashings.

White EPDM: Time-tested and built to last
In summary, technological advancements such as the 1994 formulation improvement, seam tapes, primers, puncture-resistant membrane options like 90-mil and FleeceBACK, and more robust flashing details, have made white EPDM better than ever. Of course, white EPDM has the same great reputation for hail resistance as black EPDM and features a full 60 or 90 mils of weathering resistance, which is substantially more than internally reinforced membranes. Owners, architects, and contractors can benefit from Carlisle’s white EPDM based on 33 years of experience and innovation.